This invention is in the area of controlling delivery devices for the administration of insect repellents.
Insects such as mosquitos, flies and fleas are a significant factor in the spread of many serious diseases of man and other animals. Examples include malaria, encephalitis, and a variety of parasites. They are also a general nuisance to humans and other animals. Efforts to repel these insect pests, other than with physical means, are generally ineffective for more than a few hours. There is also a significant economic loss associated with animals spending their efforts repelling insect rather than foraging.
Most means for repelling insects consist of applying an organic compound such as N,N-diethyl-m-toluamide (DEET) to the skin in an organic solvent. DEET is the most effective compound known to repel mosquitos, however, even its effectiveness is limited to a few hours. Moreover, the solvent in which it is applied to the skin also facilitates passage of the DEET through the skin, leading to undesirable toxicity, as well as irritation of the skin and eyes.
A variety of other compounds have been used to repel or kill other insects, especially flies and fleas. Most flea repellents or insecticides consist of a combination of active ingredients, many of which are not stable over a prolonged period of time. Efforts to extend the period of the effectiveness have not met with great success, although some microencapsulated forms are being marketed. These consist either of polymer or protein microcapsules incorporating the active agent to be released. The disadvantages of these reagents are that they are expensive to manufacture, they contain polymer residuals, and they are gritty and uncomfortable when applied to the skin.
It is therefore an object of the present invention to provide a composition and method to release insect repellents over an extended period of time, especially on the skin of a human or other animal.
It is a further object of the present invention to provide a composition and method to release insect repellents with minimum absorption through the skin or release of irritating chemicals at the application site.
It is another object of the present invention to provide a composition, and method of use thereof, for release of insect repellents, that is easy to prepare and stable for an extended period of time prior to use and in vivo.